<script>

setTimeout(() => {
    console.log(0)
}, 0)
new Promise((resolve, reject) => {
    console.log(1)
    resolve()
}).then(() => {
    console.log(2)
    new Promise((resolve, reject) => {
        console.log(3)
        resolve()
    }).then(() => {
        console.log(4)
    }).then(() => {
        console.log(5)
    })
    console.log(9)
}).then(() => {
    console.log(6)
})

new Promise((resolve, reject) => {
    console.log(7)
    resolve()
}).then(() => {
    console.log(8)
})

//1 7 2 3 9 8 4 6 5 0

</script>